I have a Kurt Kinetic and I also wondered if the additional flywheel could be added later. The dealer I spoke with indicated that no, it could not be added later. I'm not really into indoor training and I'm not a racer so he steered me toward the standard set up. I like the trainer, it's smooth, easy to set up, etc. It's a last resort for me though. I'd much rather be outside. I only use it when it's dark and rainy.